This invention relates to nozzled devices for applying viscous materials such as caulking or glue.
Caulking guns are well known, and may typically include, as shown in FIG. 1, a frame 10, a ratchet bar 12, a pressure plate 14 fixed to the end of the ratchet bar 12, a handle 16 and a trigger portion 18. The trigger portion 18 operates a one-way pawl device (not shown) such that squeezing the trigger 18 swill advance the pressure plate 14 to the right as shown in FIG. 1.
A container 20 of viscous caulking material, such as RTV silicone is placed in the frame portion of the gun such that the pressure plate 14 abuts the bottom 22 of the container. The container is laterally supported by curved plates 24 and is supported at its top end 26 by a bifurcated retaining member 28. The bifurcated retaining member 28 has a slot in its center into which a tapered nozzle 30 is fitted as is well known in the art. With the container 20 in place, as the trigger 18 is squeezed and the pressure plate 14 advanced, and with the bifurcated retaining member 28 preventing the forward movement of the container, the bottom 22 of the container will be moved inwardly to force the caulking material out of the nozzle 30.
The nozzle 30 provided with the container 20 is a tapered nozzle made of a flexible plastic material, with the nozzle having a maximum diameter at its base of approximately one-quarter inch. In preparing the caulking gun for operation, the user determines the desired nozzle diameter for the job to be performed, and cuts the nozzle 30 at the appropriate diameter with a scissors or the like. While this cuttable plastic nozzle provides a convenient mechanism for allowing the user to tailor the nozzle to his own particular needs, it does give rise to some difficulties. First, as mentioned above, the maximum diameter near the base of the plastic nozzle 30 is typically on the order of one-quarter inch, and it is thus difficult to effectively use the caulking gun in applications which require significantly larger nozzle diameters. Further, since the maximum diameter is near the base of the nozzle, cutting the nozzle to achieve a large diameter opening will necessarily result in a very short nozzle which is often too short to be useful. Still further, it is often the case that a single job may involve two applications of different sizes each of which requires less than the entire contents of a single container, but the nozzle diameter cannot be changed once it has been cut. Thus, for instance, it may be necessary to cut the nozzle on one container and apply half of the container contents and to then cut the nozzle on a second container and apply half of the second container's contents, after which the two half-full containers are discarded. An equally undesirable alternative would be to finish the caulking job with the same container using an improperly sized nozzle.
There have been some attempts to overcome the above-mentioned problems, but none has proven entirely satisfactory. For example, in U.S. Pat. No. 2,953,285 to McKelvey an extension nozzle apparatus is disclosed. The extension nozzle is made of a soft plastic material similar to that of the nozzle 30 in FIG. 1 of the present application, and is also tapered. The extension nozzle fits over the nozzle 30 in FIG. 1 of the present application and includes an enlarged base portion which abuts the end 26 of the caulking tube and is held in place by the bifurcated flange 28. McKelvey states that a plurality of extension nozzles of different shapes or sizes may be provided.
While McKelvey does suggest that different size extension nozzles may be provided, he points out that the extension nozzle's opening should be small so that fine or accurate caulking can be more easily accomplished, and there is no suggestion in McKelvey that the extension nozzle diameter should be larger than the maximum diameter of the tapered nozzle portion affixed to the caulking tube. Further, although extension nozzles of different sizes may be provided, it is necessary to dismantle the caulking gun in order to replace an extension nozzle. For instance, referring to FIG. 1 of the present application, the extension nozzle of McKelvey has an enlarged base portion which is secured between the bifurcated retaining member 28 and the end face 26 of the caulking tube. If the cauling tube 20 is half empty so that the pressure plate 14 is positioned near the central portion of the caulking tube, the pressure plate 14 must first be extracted from the tube 20, the tube must be removed from the caulking gun, the extension nozzle removed from the tube, a new extension nozzle placed over the tube nozzle 30, the tube reinserted into the gun, and the pressure plate reextended into the interior of the tube. After all of this, caulking can again begin with the new nozzle diameter. This is a time consuming and sometimes messy operation.
This inventor has attempted to overcome the insufficient nozzle size limitation of conventional caulking tubes by utilizing a nozzle extension similar to McKelvey except made of a copper tubing and having an enlarged diameter. While such an oversized nozzle piece is helpful, it includes a flanged base portion which fits between the bifurcated retaining member and the end face 26 of the caulking tube. Thus, as in McKelvey, it has been necessary to completely dismantle the caulking gun if a different nozzle diameter is desired.
It is therefore an object of this invention to provide a nozzle attachment for a caulking gun or the like having a nozzle diameter which is easily changed.
It is a further object of this invention to provide a nozzle apparatus having interchangeable nozzle diameters which are larger than the maximum diameter of the tapered plastic nozzle typically included as part of a caulking tube.